Discovery of millisecond radio bursts from M 87

Abstract

Highly dispersed radio pulses have been detected from M 87 at radio frequencies of 430, 606, and 1420 MHz. The pulse sweep rates scale with the third power of the observing frequency as expected from the cold plasma law. The sweep rates correspond to dispersion measures in the range 1000-5000 pc/cu cm. The pulses frequently appear grouped together separated within the group by approximately 50 msec. Peak power levels of 100 Jy and temporal widths of a few msec for individual pulses are found, and the group repetition rate is of the order of 1/sec.